Sorry, probably I missed something. Key command to show mixer on a Mac? Pointing with a mouse system shows me a hint - F3? What does it mean?
And the key command to show transport is F2.
On my retina mac book pro, it just means that if I press the fn key (on my keyboard, it beneath the UpperCase on the left, the bottom left corner of the keyboard actually) and the third key of the first row (next to esc key), the function keys are enabled and it opens the window with the mixer (F3) or the transport (F2). These key commands appear also in the Window menu — see picture attached — next to their function.